FITTING SIZES, TYPES & THREADS
UNF, UTS, UNC & UNE
major
diameter
[in]
threads per inch
major
diameter
[mm]
tap drill size
coarse
UNC
fine
UNF
extra fine
UNEF
coarse
UNC
fine
UNF
extra fine
UNEF
#0 = 0.0600
–
80
1.5240
3/64 in
#1 = 0.0730
64
72
1.8542
#53
#53
#2 = 0.0860
56
64
2.1844
#50
#50
#3 = 0.0990
48
56
2.5146
#47
#45
#4 = 0.1120
40
48
2.8448
#43
#42
#5 = 0.1250
40
44
3.1750
#38
#37
#6 = 0.1380
32
40
3.5052
#36
#33
#8 = 0.1640
32
36
4.1656
#29
#29
#10 = 0.1900
24
32
4.8260
#25
#21
#12 = 0.2160
24
28
32
5.4864
#16
#14
1/4
20
28
32
6.3500
#7
#3
5/16
18
24
32
7.9375
F
I
3/8
16
24
32
9.5250
5/16 in
Q
7/16
14
20
28
11.1125
U
25/64 in
1/2
13
20
28
12.7000
27/64 in
29/64 in
9/16
12
18
24
14.2875
31/64 in
33/64 in
5/8
11
18
24
15.8750
17/32 in
37/64 in
3/4
10
16
20
19.0500
21/32 in
11/16 in
7/8
9
14
20
22.2250
49/64 in
13/16 in
1
8
12
20
25.4000
7/8 in
59/64 in
WHITWORTH
Whitworth Size
Core Diameter
Threads
per inch
Pitch inches
Tapping Drill Size
1/16"
0.0411"
60
0.0167"
Number Drill 56 (1.2 mm)
3/32"
0.0672"
48
0.0208"
Number Drill 49 (1.85 mm)
1/8 "
0.0930"
40
0.025"
Number Drill 39 (2.55 mm)
5/32"
0.1162"
32
0.0313"
Number Drill 30 (3.2 mm)
3/16 "
0.1341"
24
0.0417"
Number Drill 26 (3.7 mm)
7/32"
0.1654"
24
0.0417"
Number Drill 16 (4.5 mm)
1/4 "
0.1860"
20
0.05"
Number Drill 9 (5.1 mm)
5/16 "
0.2414"
18
0.0556"
Letter Drill F (6.5 mm)
3/8 "
0.2950"
16
0.0625"
5/16 inch (7.94 mm)
7/16 "
0.3460"
14
0.0714"
Letter Drill U (9.3 mm)
1/2 "
0.3933"
12
0.0833"
Letter Drill Z (10.5 mm)
9/16 "
0.4558"
12
0.0833"
12.1 mm (0.4764 inch)
5/8 "
0.5086"
11
0.0909"
13.5 mm (0.5315 inch)
11/16"
0.5711"
11
0.0909"
15 mm (0.5906 inch)
3/4 "
0.6219"
10
0.1"
41/64 inch (16.27 mm)
13/16"
0.6845"
10
0.1"
18 mm (0.7087 inch)
7/8 "
0.7327"
9
0.1111"
19.25 mm (0.7579 inch)
15/16"
0.7953"
9
0.1111"
20.75 mm (0.8169 inch)
1 "
0.8399"
8
0.125"
22 mm (0.8661 inch)
1 1/8 "
0.9420"
7
0.1429"
1 1/4 "
1.0670"
7
0.1429"
1 1/2 "
1.2866"
6
0.1667"
1 3/4 "
1.4939"
5
0.2"
2 "
1.7154"
4 1/2
0.2222"
BRITISH
PIPE THREAD
Thread
size
Threads
per inch
Pitch
[mm]
Major diameter
of the thread
Gauge
length
[mm]
Corresponding pipe
[mm]
[in]
DN
OD
[mm]
OD
[in]
Thick-
ness
[mm]
1/16
28
0.907
7.723
0.304
4
1/8
28
0.907
9.728
0.383
4
6
10.2
0.40
2
1/4
19
1.337
13.157
0.518
6
8
13.5
0.53
2.3
3/8
19
1.337
16.662
0.656
6.4
10
17.2
0.68
2.3
1/2
14
1.814
20.995
0.825
8.2
12 or 15
21.3
0.84
2.6
5/8
14
1.814
22.911
0.902
16
2.6
3/4
14
1.814
26.441
1.041
9.5
20
26.9
1.06
2.6
1
11
2.309
33.249
1.309
10.4
25
33.7
1.33
3.2
1¼
11
2.309
41.910
1.650
12.7
32
42.4
1.67
3.2
1½
11
2.309
47.803
1.882
12.7
40
48.3
1.90
3.2
2
11
2.309
59.614
2.347
15.9
50
60.3
2.37
3.6
2½
11
2.309
75.184
2.960
17.5
65
76.1
3.00
3.6
3
11
2.309
87.884
3.460
20.6
80
88.9
3.50
4
4
11
2.309
113.030
4.450
25.5
100
114.3
4.50
4.5
5
11
2.309
138.430
5.450
28.6
125
139.7
5.50
5
6
11
2.309
163.830
6.450
28.6
150
165.1
6.50
5
BA
(British Assoication Screws)
BA
Outer
Diameter
Threads
per inch
0
0.2362"
25.38
1
0.2087"
28.25
2
0.1850"
31.35
3
0.1614"
34.84
4
0.1417"
38.46
5
0.1260"
43.10
6
0.1102"
47.85
7
0.0984"
52.91
8
0.0866"
59.17
9
0.0748"
64.94
10
0.0669"
72.46
11
0.0591"
81.97
12
0.0511"
90.91
METRIC THREAD
Nominal diameter
D
(mm)
Pitch
P
(mm)
Bolt Head
1st
choice
2nd
choice
coarse
fine
Height
H
(mm)
Flat size
A/F
(mm)
External diameter
A/C
(mm)
1
0.25
1.2
0.25
1.4
0.3
1.6
0.35
1.8
0.35
2
0.4
2.5
0.45
3
0.5
2.125
5.5
6.4
3.5
0.6
4
0.7
2.925
7
8.1
5
0.8
3.65
8
9.2
6
1
0.75
4.15
10
11.5
7
1
8
1.25
1
5.65
13
15
10
1.5
1.25 or 1
7.18
17
19.6
12
1.75
1, 1.5 or 1.25
8.18
19
22.1
14
2
1.5
16
2
1.5
10.18
24
27.7
18
2.5
2 or 1.5
20
2.5
2 or 1.5
13.215
30
34.6
22
2.5
2 or 1.5
24
3
2
15.215
36
41.6
27
3
2
30
3.5
2
19.26
46
53.1
33
3.5
2
36
4
3
23.26
55
63.5
39
4
3
42
4.5
3
45
4.5
3
48
5
3
52
5
4
56
5.5
4
60
5.5
4
64
6
4